In the mechanical trade and manufacturing, each half of a pair of mating connectors or fasteners is conventionally assigned the designation male or female. The “female” connector is generally a receptacle that receives and holds the “male” connector.
For example, the canonical LEGO® plastic blocks have “female” indentations on the lower surface, and “male” bosses or protrusions on the upper surfaces. Also, for example, articles like Stickle Bricks™, using interlocking plastic protrusions, and accordingly, are effectively genderless. Lincoln Logs® use a very simple form of genderless connections.